Seven Letter Aphrodisiac
by tinuelena
Summary: Spock finds that calling Jim Kirk "Captain" turns him on... a lot. Oneshot.


A/N: For my good friend and fellow GQMF Lindsay. Enjoy your porn, bb. :D

xx

The problem started immediately.

Spock, as usual, had spent hours reasoning it out. He hadn't noticed anything during the _Narada_ incident because his emotions had overtaken him. His brain, while concentrated wholly on vengeance, had no room to process the physical changes taking over his body.

Now that their mission was a routine trip to a Delta Quadrant planet to make first contact with an alien species, his sharp Vulcan mind could process what was going on.

"Mr. Spock?" Kirk's voice, laid-back and mellifluous, floated through the air.

"Yes, Captain?"

Usually, Starfleet regulation slacks were not this tight, and Spock found it highly irritating—and illogical—that addressing James Kirk by his official title provoked such a reaction.

"How are we doing?"

"The temporal anomaly will not cross our path, Captain. After we depart from Niobe IV, it will be out of our quadrant."

"Thanks."

He returned to his screen and surreptitiously adjusted himself.

"Oh, Mr. Spock," Kirk called out, "one more thing. I have a favor to ask you."

"Yes, Captain?"

"Lieutenant Uhura tells me that you've studied their dialect. I'd like you to beam to the surface of the planet with us in order to assist in communicating."

"Of course, Captain."

It was at this point that he realized a simple "of course" would have sufficed, and a light turned on; at some subconscious level, he enjoyed the arousal. He turned back to his station. _Illogical, _his brain scolded, as he hit a key several times in succession. _Illogical. Illogical._

Jim Kirk was nothing if not observant, and though he didn't really know why he'd been checking out his first officer, he'd definitely noticed the little shudder that coursed through those Vulcan veins every time Spock called him "Captain." He liked it.

He also liked to push buttons.

xx

That night, Spock spent his free time doing the only thing he knew how to do when something confused him—research.

Typing in a search string including the phrases "arousal" and "position of authority," Spock came across an interesting set of articles that led him to the conclusion that he was what Terrans called a "submissive." He was in the middle of analyzing the psychology behind submissive tendencies when a familiar figure appeared in his doorway. Immediately, he stood.

"Mr. Spock." Kirk grinned.

Spock, in an attempt to prevent another physical reaction, simply inclined his head in response. "What can I do for you?"

Kirk raised an eyebrow. "That's an uncharacteristic greeting."

"What do you mean?"

As he made his way further into Spock's quarters, the door slid shut behind him. "Ever since my promotion, I don't think there's been one exchange between us where you haven't used my title."

"Would you prefer to be addressed by your first name?" Spock asked calmly.

"No," replied Kirk, a husky note in his voice, still advancing on his first officer. "Call me Captain."

Spock stepped back. "Alright. What can I do for you, _Captain?"_

"Several things."

Kirk's eyes burned, and Spock nearly gasped at the realization. _He knows. _"You," Spock began, "are aware of the effect—"

"Oh, I'm aware," Kirk growled. Spock was inches away from him, back to the wall, with nowhere to go. He knew that his first officer could take him down in a flash with a nerve pinch, but his instincts buzzed with one thought: _that's not the way Spock wants to touch me. _"Are you aware of my intentions?"

"I have formed a hypothesis…" Spock momentarily lost power of speech as Kirk arched his pelvis into Spock's own.

"Take your shirt off, Spock."

Spock merely blinked at him, still trying to process the reality of the encounter.

Kirk narrowed his eyes. "That's an order."

Almost without volition, Spock lifted his blue uniform shirt from over his head and tossed it onto the floor.

"The rest of it, too."

Spock obeyed without question, pushing his black pants and boxer-briefs to the floor.

Hungrily, Kirk eyed his first officer, letting his gaze linger on the rigid erection and its deep green tinge.

As he looked down at himself, Spock realized that, from his view, this was the most acute angle his body had ever produced.

Kirk moved in swiftly, still clothed, unable to exercise any amount of self-control. As his hand brushed Spock's fiery skin, he suddenly realized that he'd wanted this far longer than he'd thought, that the thick lust driving through his veins couldn't be satiated by sleeping with hot blonde xenolinguists. Subconsciously, he'd always been attracted to his first officer, to his cold logic and his hot touch, to the sharp angles of his face, to the oddly sensual slant of his eyebrows. And he felt strangely soothed by this knowledge.

Without instruction, Spock moved to lift Kirk's shirt from over his head. Kirk could practically hear his thoughts—_it is illogical for one of us to be fully undressed while the other is fully dressed,_ or some Spock-ism of that sort. Everything revolved around logic.

_There's no logic in this, _Kirk thought, as Spock brought fingertips to his face.

_No,_ Spock thought back. _This is not logical at all._

At first, Kirk was surprised, but then he remembered the meld with Spock Prime, remembered the transfer of emotions, remembered the faint echo of strong affection among all the ache of his failure to save Romulus and the pain of watching Vulcan's destruction. Again, a sudden onslaught of realization—_the other Spock loved his Kirk, too._

_I am not surprised by this._ Spock's voice inside his head felt like a balm to his brain, some odd amalgamation of comfort and a strong aphrodisiac.

Then—_love? Did we just—_

The closest thing to a Vulcan smile Kirk had ever seen appeared on Spock's lips. _Perhaps. Now, however, is not the time. I wish to further explore the phenomenon of language as an aphrodisiac. I admit I am curious to find out whether I truly am a "submissive…"_

As Kirk pondered this, Spock let his hands fall to his sides, waiting for his commanding officer to take the reins.

Kirk edged closer, pinning Spock to the wall, letting the relative cool of his skin mingle with Spock's radiant warmth. Spock wasn't used to contact like this, he could tell, and he planned to take full advantage.

He let his fingertips trail gently down Spock's side, raising goosebumps on his skin, and bent to trace the slope of one pointed ear with his tongue. Spock rewarded him with the faintest of sighs, and even that tiny indication that Spock's hardened self-control had begun to vanish set his blood on fire.

Kirk drew his fingers across the top of Spock's thigh, his pelvis, over his toned stomach. He knew it would be fun to draw it out, to tease Spock for hours, but he didn't have the patience. The need for satisfaction, for connection, was far too great.

Without a second thought, he wrapped strong fingers around Spock and began to stroke slowly. He watched as his first officer's eyes fluttered, as his lips parted slightly. "Let me guess," Kirk said coyly. "Masturbation isn't practiced on Vulcan? Illogical?"

"You are correct." His voice was full of breath and lacked the usual tonal quality of gravelly ice. "Pleasure is an emotion…"

Kirk tightened his grip, and Spock's knees buckled. "Go on."

Spock exhaled. "Sexual activity on Vulcan is… limited to procreation."

A mischievous grin lit Kirk's face. "Fascinating." He licked his hand while Spock watched, and the sight of Kirk's tongue on skin seemed to undo him even further. As Kirk took him in his wet palm, he let out a tiny moan. "Why don't you try out that linguistic aphrodisiac, Commander?"

"Captain…"

The word was airy and deliberate, and Kirk could _feel_ Spock growing harder. _God damn._ He thumbed the soft patch of skin just below the head, and Spock dug his fingernails into Kirk's lower back. "Captain—I—"

Fragmented speech. From _Spock_. Kirk brought his left hand down to cup and massage, quickening his rhythm with the right. Spock clutched frantically at him, his knees bent, legs trembling, barely able to stand.

"The—bed—" gasped Spock, and an incomplete sentence had never sounded so hot.

Kirk obliged, setting him free, and Spock instantly hit the bed. Kirk scrambled out of his pants, eager to press his own erection into Spock's thigh, aching to make him lose all control.

Climbing into bed, Kirk couldn't help but let his hands travel Spock's torso again; he stopped short when his fingers detected a dull thump in the Vulcan's chest.

"Your heart is where a human heart is," Kirk said suddenly, shock on his face. "So you have human physical characteristics along with your Vulcan ones." He traced one dark eyebrow with his index finger.

"You are educated in Vulcan anatomy?" came Spock's surprised response.

At this, Kirk couldn't help but smile. "Should I prove it?"

Spock had never claimed to understand the complexities of human pranks, but serving alongside Montgomery Scott had given him a working knowledge of sexual innuendo, and he knew what James Kirk's cheeky smile was suggesting.

"I would appreciate it if you would," he replied.

"Don't be shy about using that word."

Spock shivered. "Please, Captain."

Satisfied with the response, Kirk held his index finger to Spock's mouth. Intuitively, Spock knew to open his mouth, to coat his captain's finger with saliva; though he knew human fingers weren't as responsive as Vulcan ones, he swirled his tongue around in ways that made blood rush to Kirk's nether regions.

Kirk slid his finger out of Spock's mouth and gently separated the firm hills of flesh on his first officer's backside, then eased it slowly inside. Watching Spock's face was like a drug; soft puffs of air escaping from between smooth, warm lips, the lightening of his irises from deep chocolate to rich caramel, the fluttering of dark eyelashes against pale skin. As he readied Spock's opening, a thought crossed his mind—_this has got to be awkward for him. Vulcans kiss with their fingers. He has to feel like I'm—_

Spock let out a low moan, and Kirk shivered. _Or maybe I've got a kinky Vulcan on my hands._ He smiled at the thought.

Impatiently, Kirk slid a second digit inside and continued to move, working his fingers like scissors, gently stretching him. Spock's eyes had drifted shut; his breath grew more ragged, and he was now pressing back into Kirk's open palm. "Captain— what is the purpose—it would make far more sense for you to enter me promptly—"

"Don't give me that logic bullshit," Kirk said. "This is for your own good."

Spock fixed him with a firm gaze. "I am a Vulcan," he panted. "I am able to handle pain—"

"No logic," Kirk pressed.

Spock let out a sound that could only be called a whine, and drove his fist into the mattress. "Please, Captain."

"Why?" God, he could get used to this.

His eyes glittered. "I cannot accurately express how badly I want to feel this sexual experience," he articulated; if it wasn't Spock, Jim would have laughed at the bluntness of the statement. Conversely, he'd never been more turned on in his life.

Obliging Spock's request, he withdrew his fingers. "Get me wet," he commanded.

Spock raised an eyebrow.

"That thing you were doing to my finger," Kirk breathed. "Do that."

Wordlessly, Spock bent down and easily took his captain into his mouth, pushing his rough tongue against Kirk's sensitive skin, repeating the patterns he'd used moments before. _Shit, _Kirk thought, bucking his hips against Spock's face, _keep this up and I'll come in seconds… _so _good…_

Kirk wrenched away from the damp cave of Spock's mouth before he lost all control, and flipped his first officer onto his back.

"I was under the impression," Spock said hesitantly, "that I am supposed to be positioned on my hands and knees?"

He smiled. "You don't have to give in to every submissive cliché." Kirk slid a pillow underneath Spock and lifted his legs, letting his ankles rest on his broad shoulders. "Plus, I hear it feels better this way. And I get to watch your face."

At this, Spock actually blushed, his face turning a lovely shade of green, and Kirk was reminded of the dawn of spring back home in Iowa—the verdancy of new grass, budding leaves, stems pushing their way out of the earth.

_New things. _Smiling inwardly, Kirk positioned himself at Spock's opening. "Ready?"

Spock nodded, his face a cloud of curiosity mixed with uncertainty, and Kirk resolved to be gentle—at least to begin with.

As he slid inside, Spock's eyes flew open, round and bright and honey-colored, and he let out the most glorious moan. Kirk held his breath; his Vulcan first was exquisitely tight, and the heat was overwhelming. Dazedly, he began to move. "Spock… oh, _fuck, _Spock…"

Spock made a strangled sort of noise, and it spoke volumes—_I want to let go, but I'm Vulcan, I am not programmed to deal with overwhelming pleasure, I am not accustomed to expressing such strong emotion—_Kirk could translate it all from the ache in his eyes, and he knew how to give him release.

He bit down gently on his shoulder. "Let me hear it, Spock."

"Captain… _Captain…_" The words hit Kirk's ear like a waterfall, and he felt Spock's erection thumping against his stomach, hard and pulsing.

Spock's hand drifted over his own pelvis, and he gazed up at Kirk. "Captain. May I…" He trailed off, embarrassed.

"Oh, God, Spock… you're asking _permission?" _

Spock's voice was a whisper. "Yes."

He wasn't sure why this turned him on so much, but his body was at warp factor ten and climbing. No way would he last much longer. "Permission granted," he managed to gasp out.

Spock wrapped his own fingers around himself, copying Kirk's earlier ministrations, and the sight of his first officer pleasuring himself nearly pushed Kirk over the edge. "Oh, God. Spock…" Transfixed, he stilled for a moment, unable to concentrate on anything but the motion of that hand.

"Why have you stopped?"

Kirk had barely noticed, and began to move again. Spock tightened around him. "Spock," he whispered, "Spock…" He clutched the sheets and held his breath. "Oh, _fuck… _Spock… I'm close, I'm…" He glanced at his first officer's face; his eyes were dark and greedy, as intense as the time he'd almost choked him to death on the bridge, but bright, _so_ bright… "Spock… I'm… oh _God, _yes… yes—"

Kirk arched into him, shuddering, coming in one long, fierce stream. Spock's expression was almost primal as he savored the feeling of being filled by Kirk, his lip curled back into a satisfied snarl, hungrily drinking in the sight of Kirk's open mouth, his eyes rolling back, the pink flush spreading across his chest.

As Kirk finished and stilled, Spock tugged at his hand, pushing his cool fingers around the burning skin of his erection. "Please," Spock begged. "I want to."

The realization that Spock just ended a sentence with a preposition flitted through Kirk's brain, and he decided to tease him about it… later. Teasingly, Kirk removed his hand, and Spock gave a little grunt of protest.

"Shh. You'll like this better," Kirk promised, and lowered himself onto his first officer.

His eyes flew open as Kirk encased him, expertly moving up and down, and he let out a throaty moan. "Captain… this… is highly…"

Kirk clenched and began to move in circles; Spock involuntarily bit down on his impeccably smooth bottom lip.

"Highly what?" teased Kirk.

Spock said nothing; his eyelids fluttered and one hand clutched at Kirk's back.

"Speechless?"

"Captain, I—mmm, _ni rom—_"

Spock slipped into his native language, and though Kirk didn't speak a word of Vulcan, it wasn't hard to guess at a translation.

_ "Khart-lan… ah… sanoi, sanoi…"_

He thrusted harder, moving his hips, staring directly into Spock's eyes.

_"Khart-lan… _Captain…!"

He flew into a sitting position, fingers digging into Kirk's neck, and came in a series of short, shaky bursts. Instantly, he fell back onto the bed, exhausted.

Satisfied, Kirk gently lifted himself from Spock's body and settled in next to him. "Scientific experiment over?"

"Mmm. Yes. My hypothesis has been proven correct."

"So I've outlived my usefulness?"

Gently, Spock set his hand on Kirk's hip. "I am generating ideas for several other scientific experiments as we speak."

"Maybe next time you can pretend I'm an angry Romulan holding you captive."

Spock's lips curved into a small smile. "Good night, Jim."


End file.
